False. Vapour barriers, together with air barriers, prevent moisture from escaping into the walls. In this sense vapour barriers make you more aware of the quantity of moisture you have generated in your house. Condensation problems are caused by generating too much moisture and/or having too little fresh-air ventilation inside the house. A vapour barrier, together with an air barrier, only brings a problem that was previously inside the walls out into the open and onto the windows.